Rewrite ${((7^{-5})(4^{6}))^{-9}}$ in the form ${7^n \times 4^m}$.
Explanation: ${ ((7^{-5})(4^{6}))^{-9} = (7^{(-5)(-9)})(4^{(6)(-9)})} $ ${\hphantom{ ((7^{-5})(4^{6}))^{-9}} = 7^{45} \times 4^{-54}} $